Causes of Sewer Gas Smell Inside a House

A persistent “sewer gas” or rotten-egg smell inside a home is most often linked to plumbing and drain systems that are failing to keep gases contained. While the odor is unpleasant, it can also signal a ventilation or blockage issue that may require prompt attention.

“Sewer gas” typically refers to gases produced in wastewater, including hydrogen sulfide, which can smell like rotten eggs. These gases can enter a house when they bypass the traps and vents designed to keep them out.